The present invention relates to methods and devices for improved precision in finding one or more nerves and then interrupting the transmission of neural signals through the target nerve. The treated nerve can be rendered incapable of transmitting neural signals for a select duration of time, where such a duration can be on a temporarily basis (e.g., hours, days or weeks) or a longer term/permanent basis (e.g., months or years). One embodiment of the apparatus includes a precise energy source system which features energy transfer elements that are capable of creating areas of nerve destruction, inhibition and ablation with precision.
The human nervous system sends and receives signals to convey both sensory information, such as pain, heat, cold and touch, as well as command signals that control muscle movement. There are many cases where disrupting the neural signal can provide preventative, therapeutic, and/or cosmetic benefits to an individual. For example, extraneous, undesired, or abnormal signals can be generated (or are transmitted) along nervous system pathways. For example, the pinching of a minor nerve in the back can cause extreme back pain. Similarly, the compression or other activation of certain nerves can induce significant or constant pain. Certain diseases also may compromise the lining of nerves such that neural signals spontaneously generate. This spontaneous generation can cause a variety of maladies, from seizures to pain or (in extreme conditions) even death. Abnormal signal activations can cause many other problems including (but not limited to) twitching, tics, seizures, distortions, cramps, disabilities (in addition to pain), other undesirable conditions, or other painful, abnormal, undesirable, socially or physically detrimental afflictions.
In some situations, the normal conduction of neural signals causes undesirable muscle causes frown lines that can result in permanent distortion of the brow (or forehead); giving the appearance of premature aging. Interrupting the neural signal of the corrugator supercilli activation nerves can alleviate the distortion of the brow or forehead.
Traditional electrosurgical procedures use either a unipolar or bipolar device connected to an energy source. A unipolar electrode system includes a small surface area electrode, and a return electrode placed in contact with the body at a location separate and spaced from the small surface area electrode. The return electrode is generally larger in size, and is either resistively or capacitively coupled to the body. Since the same amount of current must flow through each electrode to complete the circuit. Because the return electrode is typically a large surface area the decreased current density allows heat to be dissipated over the larger surface area. In some cases, it is desirable to locate return electrodes in areas of high blood flow (such as the biceps, buttocks or other muscular or highly vascularized area) so that any generated heat generated is rapidly carried dissipated. One advantage of a unipolar system is the ability to place the unipolar probe exactly where it is needed and optimally focus electrosurgical energy where desired. A resistive return electrode would typically be coated with a conductive paste or jelly. If the contact with the patient is reduced or if the jelly dries out, a high-current density area may result, increasing the probability for burns at the contact point.
Typical bipolar electrode systems are generally based upon a device having electrodes of opposite polarity. Each electrode is connected to one of the two poles of the electrosurgical generator. When the electrosurgical energy is applied, it is concentrated (and focused) so that current flows between the electrodes of opposite polarity in the region of the device. Assuming the instrument has been designed and used properly, the resulting current flow will be constrained within the target tissue between the two surfaces.
Treatments for the elimination of glabellar furrowing have included surgical forehead lifts, resection of corrugator supercilli muscle, as described by Guyuron, Michelow and Thomas in Corrugator Supercilli Muscle Resection Through BlepharoplastyIncision, Plastic Reconstructive Surgery 95 691-696 (1995). Also, surgical division of the corrugator supercilli motor nerves is used and was described by Ellis and Bakala in Anatomy of the Motor innervation of the Corrugator Supercilli Muscle: Clinical Significance and Development of a New Surgical Technique for Frowning, J Otolaryngology 27; 222-227 (1998). These techniques described are highly invasive and sometimes temporary as nerves regenerate over time and repeat or alternative procedures are required.
Another less invasive procedure to treat glabellar furrowing involves injection of botulinum toxin (Botox) directly into the muscle. This produces a flaccid paralysis and is best described in The New England Journal of Medicine, 324:1186-1194 (1991). While minimally invasive, this technique is predictably transient; so, it must be re-done every few months.
Specific efforts to use RF energy via a two needle bipolar system has been described by Hernandez-Zendejas and Guerrero-Santos in: Percutaneous Selective Radio-Frequency Neuroablation in Plastic Surgery, Aesthetic Plastic Surgery, 18:41 pp 41-48 (1994) The authors described a bipolar system using two parallel needle type electrodes. Utley and Goode described a similar system in Radio-frequency Ablation of the Nerve to the Corrugator Muscle for Elimination of Glabellar Furrowing, Archives of Facial Plastic Surgery, January-March, 99, VI P 46-48, and U.S. Pat. No. 6,139,545. These systems were apparently unable to produce permanent results possibly because of limitations inherent in a two needle bipolar configuration. Thus, as is the case with Botox, the parallel needle electrode systems would typically require periodic repeat procedures.
There are many ways of properly locating an active electrode near the target tissue and determining if it is in close proximity to the nerve such that the treatment is limited to the area of interest. In many applications, there is a need to ensure that the nerve is located and treated to establish a desired effect while minimizing collateral damage to surrounding tissues. Such is especially the case in cosmetic application.
Various stimulation devices have been made and patented. One process of stimulation and ablation using a two-needle system is disclosed in U.S. Pat. No. 6,139,545. The stimulation may also be implemented negatively, where tissue not responsive to stimulation is ablated as is described in U.S. Pat. No. 5,782,826 (issued Jul. 21, 1998).